my guess is -> cooling radiator in any way got a fine crack

it looks like air from driving is spreading the coolant liquid in that area

 

Definitely seems like air while driving is spreading it all over on that side. The stains have stretched far past the cats and trans pan.

I should have added that I don't see even a hint of staining anywhere on the radiator fins or hoses in or out of radiators. They look practically brand new. I guess there could be a crack on the side that faces away from the sides that I can see easily, though.

 

fill it up with coolant, drive to the next workshop without your lower engine protector, let the cooling system check with high pressure while the engine is hot and you will see, what part wants to be changed.

 

Maybe get a camera, like a GoPro, and some LED lighting, fasten them under the hood in various places, and go for some drives. Maybe you can catch the leak in the act.

 

See post No.4 and the endoscope duel camera with LED light, requirement for some investigative inspection for those difficult to access places.

Looks a little more forward & RHS than pouring down the back of the engine from the engine valley.

Could be the rear heater manifold spraying out on the right hand side, since leak pressure and temperature rated. But could be many things!! As you are seeing.

Without removing/lifting things like expansion tank and the windscreen finisher, and inspecting hard to say without playing guessing games.

Easier poking around with the camera in and around the expansion tank area, and move over to the usual suspects.

 

Thanks, guys. Sounds like getting some cameras setup, taking it out for a vigorous drive and looking for the leak hot and real-time is my next best option.

I will update next week, since the wifey and I are taking a long weekend trip starting tomorrow. The Gray Ghost will sadly not be participating this time. I told her since she is misbehaving she stays in the garage this weekend. The car, not the wifey. 🤔😀

 

A Very Wise move. Vigorous diving, and Hot leaks, which could pop big at anytime and end in disaster would not be good.

On the Car, not the Wifey that is.

 

Truer words have never been written. lol

 

Here is what I would do. Wrap some cloth material around areas where you suspect a leak. Block radiator side from engine by cloth material or a piece of carboard. Drive around, shut down the engine and expect. You should be able to see from stains the area where the leak is coming from. Then, repeat the test focusing on the specific area. Just make sure material does not get loose and does not touch belts or exhaust.

 

Also, big cause of overheat is thermostat. What temp are the water lines on either side of it at operating temp. You should know if the thermostat is opening just using an infrared thermometer. I get you're trying to find the leak but if you have opportunity to find out why it's leaking, all the better. I haven't been under my hood much in the past couple years. From those pics, is it possible leak is really overflow tank spilling out? Not a fan of wrapping the engine I any cloth. Consider Fluorescent dye.

 

Good point, but better monitoring the engine CW temp via the OBD port, with live data monitoring real time. see post one, 4k to 6k revs under load. So sticky thermostat is an option.

 

Thanks guys. Since I haven't seen an overheating alarm I assumed that wasn't a problem, but it makes sense not to assume anything at this point. I'll get some live temp data from the OBD port next week. Cheers.

 

Overheating alarm? Does it have one? (Yes, see below page 186)

I thought is was CW low level expansion tank only?

Could be wrong, but there are a awful lot of overheated v6 and V8 engines due to complete water loss on plastic pipe failures.

Would tie in nicely, with expansion tank being sick at high load, temp and a duff sticky thermostat.

Yes it does, in the screen display, Engine Overheating, page 186.

 

I have just checked your car details 60k and a 2010 XKR. Is it the original thermostat?

Having just checked my 2013 with a 10-2012thermostat, 3.0Ltr , 66k miles on this thermostat and comparing the operation to the new plastic OEM thermostat, and the Alloy bodied thermostat for operating at temperature 100deg c, (boiling pan of water)

Checked the thermostat plunger movement cold to hot to cold. and measured the overall lengths.

The old original thermostat, was rather jerky in operation, not as smooth as the others. So well worth changing out. The rating stamped on the top was 95deg C.

The top alloy pipe was reading 100deg c at prolonged idle, and the fan was not running fast. as checked with IR gun. No obvious spillage on top of the expansion tank, but the felt sound deadening, below, and the bonnet sound deadening material was stained with salts. and both were clean after the maintenance last sumer.




Alloy, new OEM, and old original thermostats


the internals. all springs were same length, the spring carrier was slightly eroded at the top, and the top spring cap was cracked.



Yes I would definitely monitor the cw temperature in operation and see if it controls smoothly.


95deg stamped.

 

Great info. I sincerely appreciate the effort in documenting all of that. I will add these to my list of items to check and/or monitor.